Abstract
In International Union for Conservation of Nature (IUCN) Red List assessments, extent of occurrence (EOO) is a key measure of extinction risk. However, the way assessors estimate EOO from maps of species' distributions is inconsistent among assessments of different species and among major taxonomic groups. Assessors often estimate EOO from the area of mapped distribution, but these maps often exclude areas that are not habitat in idiosyncratic ways and are not created at the same spatial resolutions. We assessed the impact on extinction risk categories of applying different methods (minimum convex polygon, alpha hull) for estimating EOO for 21,763 species of mammals, birds, and amphibians. Overall, the percentage of threatened species requiring down listing to a lower category of threat (taking into account other Red List criteria under which they qualified) spanned 11-13% for all species combined (14-15% for mammals, 7-8% for birds, and 12-15% for amphibians). These down listings resulted from larger estimates of EOO and depended on the EOO calculation method. Using birds as an example, we found that 14% of threatened and near threatened species could require down listing based on the minimum convex polygon (MCP) approach, an approach that is now recommended by IUCN. Other metrics (such as alpha hull) had marginally smaller impacts. Our results suggest that uniformly applying the MCP approach may lead to a one-time down listing of hundreds of species but ultimately ensure consistency across assessments and realign the calculation of EOO with the theoretical basis on which the metric was founded.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 362-370 |
| Number of pages | 9 |
| Journal | Conservation Biology |
| Volume | 30 |
| Issue number | 2 |
| DOIs | |
| State | Published - Apr 1 2016 |
Fingerprint
Keywords
- Distribution maps
- IUCN Red List
- Threatened
ASJC Scopus subject areas
- Ecology
- Nature and Landscape Conservation
- Ecology, Evolution, Behavior and Systematics
Cite this
Impact of alternative metrics on estimates of extent of occurrence for extinction risk assessment. / Joppa, Lucas N.; Butchart, Stuart H M; Hoffmann, Michael; Bachman, Steve P.; Akçakaya, H. Resit; Moat, Justin F.; Böhm, Monika; Holland, Robert A.; Newton, Adrian; Polidoro, Beth; Hughes, Adrian.
In: Conservation Biology, Vol. 30, No. 2, 01.04.2016, p. 362-370.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Impact of alternative metrics on estimates of extent of occurrence for extinction risk assessment
AU - Joppa, Lucas N.
AU - Butchart, Stuart H M
AU - Hoffmann, Michael
AU - Bachman, Steve P.
AU - Akçakaya, H. Resit
AU - Moat, Justin F.
AU - Böhm, Monika
AU - Holland, Robert A.
AU - Newton, Adrian
AU - Polidoro, Beth
AU - Hughes, Adrian
PY - 2016/4/1
Y1 - 2016/4/1
N2 - In International Union for Conservation of Nature (IUCN) Red List assessments, extent of occurrence (EOO) is a key measure of extinction risk. However, the way assessors estimate EOO from maps of species' distributions is inconsistent among assessments of different species and among major taxonomic groups. Assessors often estimate EOO from the area of mapped distribution, but these maps often exclude areas that are not habitat in idiosyncratic ways and are not created at the same spatial resolutions. We assessed the impact on extinction risk categories of applying different methods (minimum convex polygon, alpha hull) for estimating EOO for 21,763 species of mammals, birds, and amphibians. Overall, the percentage of threatened species requiring down listing to a lower category of threat (taking into account other Red List criteria under which they qualified) spanned 11-13% for all species combined (14-15% for mammals, 7-8% for birds, and 12-15% for amphibians). These down listings resulted from larger estimates of EOO and depended on the EOO calculation method. Using birds as an example, we found that 14% of threatened and near threatened species could require down listing based on the minimum convex polygon (MCP) approach, an approach that is now recommended by IUCN. Other metrics (such as alpha hull) had marginally smaller impacts. Our results suggest that uniformly applying the MCP approach may lead to a one-time down listing of hundreds of species but ultimately ensure consistency across assessments and realign the calculation of EOO with the theoretical basis on which the metric was founded.
AB - In International Union for Conservation of Nature (IUCN) Red List assessments, extent of occurrence (EOO) is a key measure of extinction risk. However, the way assessors estimate EOO from maps of species' distributions is inconsistent among assessments of different species and among major taxonomic groups. Assessors often estimate EOO from the area of mapped distribution, but these maps often exclude areas that are not habitat in idiosyncratic ways and are not created at the same spatial resolutions. We assessed the impact on extinction risk categories of applying different methods (minimum convex polygon, alpha hull) for estimating EOO for 21,763 species of mammals, birds, and amphibians. Overall, the percentage of threatened species requiring down listing to a lower category of threat (taking into account other Red List criteria under which they qualified) spanned 11-13% for all species combined (14-15% for mammals, 7-8% for birds, and 12-15% for amphibians). These down listings resulted from larger estimates of EOO and depended on the EOO calculation method. Using birds as an example, we found that 14% of threatened and near threatened species could require down listing based on the minimum convex polygon (MCP) approach, an approach that is now recommended by IUCN. Other metrics (such as alpha hull) had marginally smaller impacts. Our results suggest that uniformly applying the MCP approach may lead to a one-time down listing of hundreds of species but ultimately ensure consistency across assessments and realign the calculation of EOO with the theoretical basis on which the metric was founded.
KW - Distribution maps
KW - IUCN Red List
KW - Threatened
UR - http://www.scopus.com/inward/record.url?scp=84960089414&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84960089414&partnerID=8YFLogxK
U2 - 10.1111/cobi.12591
DO - 10.1111/cobi.12591
M3 - Article
C2 - 26183938
AN - SCOPUS:84960089414
VL - 30
SP - 362
EP - 370
JO - Conservation Biology
JF - Conservation Biology
SN - 0888-8892
IS - 2
ER -